Portals (Mage, Shattrath, and the Warlock soul portals) have new sounds associated with them (thanks, Xtra)

Prince in Karazhan has gotten wise to some previously "safe" areas (thanks, Shumina)

The Battlemasters have been working out -- they're bigger and you can't go through them any more (thanks, Esfand)

Takes less casts to skill up fishing (thanks, nearlysober)

Brewfest keg now has a casting circle, doesn't just appear (thanks, kozaj)

Supremus in Black Temple has also been working out, and is much bigger than before (thanks, Mats)

The quest giver for the Aether Ray wrangling quest (Skyguard Khatie) is now actually mounted on a nether ray (thanks, Thallid)

Warriors' Whirlwind sound has changed (thanks, dabronx and fletcher)

Rep grind for Sporeggar appears to be easier (thanks, Al)

A few other changes are also floating around, but most of the others I've heard sound like fixable bugs and/or problems with addons after the patch. If you have any more changes, feel free to throw them in the comments below. Thanks to everyone who noticed something different about the patch -- it's good to find out what Blizzard's been up to for the past few months.